Ethereal Spellbook (3.5e Equipment)

From D&D Wiki

Ethereal Spellbook: This spellbook has a dark purple cover made from the skin of an ethereal marauder and covered with an assortment of unusual runes. The pages are made from paper created from the wood of an ash tree and treated with an ironwood spell making them as supple as silk yet strong as steel. The ink is distilled from the blood of a displacer beast.

The book allows its owner to send it to the ethereal plane where it patiently follows the owner around waiting to be summoned. Dismissing the book is as easy as saying "Taril", while summoning requires picturing the book in your mind and calling out "Lirat". Attuning oneself to a found book takes 24 hours of meditation. Until then the pages in the book are blank (although a true seeing spell or similar effect would reveal the writing).